Some years ago, I found I had a stuck end cap on a 2D cell mag light. Frustrating. I gingerly tried tapping on the end and using a rubber strap wrench, and got nowhere. I decided that if I was careful, maybe I could grab the knurl on the endcap with a big set of channel locks and not screw it up too bad if I didn't let them slip. Put some force on it, got nowhere.
Now I'm getting annoyed. I've got an hour into screwing around with this and have got nowhere. I decide to hell with it, I'm going to really force it, and worst case scenario I'll have to turn the end cap down a little to clean up damage my channel locks do grabbing on it.
I still got nowhere. Time for a 24 inch pipe wrench!
Not. Even. Thinking about unscrewing.
Now I've written off the whole thing, and decided piss on it... and bandsawed the end clean off.
That got me inside, to a corroded mess. I cut the other end off and got the batteries out. Not sure if I hammered them out or used the press. Rayovac D cells. I took a few pictures of this whole mess, and wrote a polite but displeased email to rayovac including pics, stating that their batteries leaked and destroyed my $20 flashlight.
A couple days later, I got a reply email. A representative said to me that normally they required the damaged product to be sent to them, but in this case they would honor the warranty immediately, and did not need to send them anything.
About a week later, I got a package in the mail with two new rayovac D cells. Well... it's something, I guess. BUT WAIT... a few days past that, I received another piece of mail, which was a $20 check made out to me from the rayovac corporation.
I used the money plus a little more to buy a new LED light, which I still have and use.